The United States has emerged as the principal obstacle to the most ambitious global climate measure to be considered in 2026: a binding levy on the carbon emissions produced by international shipping. With the International Maritime Organization (IMO) preparing for the next round of Marine Environment Protection Committee (MEPC) negotiations, the Trump administration has formally signalled it will not support the proposed greenhouse gas pricing mechanism, requesting procedural delays and challenging the legal basis on which the IMO is acting. The move has set Washington on a collision course with the European Union, the United Kingdom, China and a coalition of Pacific island states, and threatens to derail what would have been the first sector-wide global carbon price ever agreed under a United Nations body.

For UK investors, the dispute matters far beyond the shipping lanes. It tests the durability of multilateral climate governance at a moment when carbon pricing is being woven into the architecture of global trade. It raises fresh questions about US-EU regulatory divergence, the credibility of the UN climate process heading into COP31, and the pricing of risk in everything from container freight to alternative fuels. London, which hosts the IMO and is home to one of the world's largest concentrations of shipbroking, marine insurance and maritime law expertise, sits squarely in the middle of the dispute.

Background on the IMO carbon levy

How the proposal evolved

The IMO has been edging towards a global shipping carbon price for the better part of a decade. The 2018 Initial GHG Strategy committed the sector to halving emissions by 2050. That target was upgraded in July 2023 to a net-zero by, or close to, 2050 ambition, with indicative checkpoints of a 20 to 30 per cent cut by 2030 and 70 to 80 per cent by 2040. International shipping accounts for approximately 3 per cent of global greenhouse gas emissions, comparable to Germany's national footprint, and is one of the few sectors not covered by the Paris Agreement's nationally determined contributions.

To achieve those goals, the IMO has been designing a basket of measures combining a technical standard - the Global Fuel Standard, which would tighten the carbon intensity of marine fuel over time - with an economic instrument. The economic instrument under discussion is a levy of between 150 and 300 US dollars per tonne of carbon dioxide equivalent, applied to bunker fuel emissions. Revenue, projected at between 40 and 80 billion dollars annually, would be channelled through an IMO-administered Net Zero Fund supporting research, alternative fuel infrastructure and a just transition for developing maritime states.

MEPC 83 and the road to MEPC 84

At MEPC 83 in spring 2025, member states agreed in principle on the architecture of a hybrid measure but deferred the precise pricing, exemption thresholds and Revenue-recycling mechanism. MEPC 84, scheduled for early 2026, was meant to finalise the legal text for adoption later in the year, with entry into force from 2027. That timetable is now in doubt. The US delegation has tabled a series of procedural objections, requested extensions to working group timelines and indicated that any binding instrument approved without consensus would not be ratified by Washington.

Latest developments: the US delay

Washington's formal position

The Trump administration has positioned its objection on three grounds. First, it argues that a global shipping levy would constitute a tax on US consumers and exporters, in conflict with the constitutional reservation of taxation powers to Congress. Second, it questions whether the IMO has the legal authority under the MARPOL Annex VI framework to impose what the US characterises as a fiscal measure rather than a pollution-control regulation. Third, it frames the levy as economically discriminatory against fossil-fuel producing nations, including the US, which is now the world's largest exporter of liquefied Natural Gas and Crude Oil.

In private diplomatic correspondence reported by trade press, the US has also linked its position to broader grievances on EU climate policy, including the Carbon Border Adjustment Mechanism (CBAM) and the EU Emissions Trading System (ETS) extension to shipping. Washington has signalled that retaliatory trade measures could follow if the EU continues to apply ETS charges to US-flagged vessels calling at European ports.

A pattern, not an isolated move

The IMO delay sits within a wider pattern of US disengagement from multilateral climate governance under the second Trump administration. The US formally re-initiated Withdrawal from the Paris Agreement in early 2025, has moved to repeal substantive portions of the Inflation Reduction Act, and has scaled back climate finance pledges to the Green Climate Fund. The IMO position is consistent with that trajectory but has particular significance because shipping had been viewed as a relatively technocratic, consensus-driven forum insulated from front-line political battles. That insulation has now eroded.

The coalition pushing back

A broad coalition is pushing in the opposite direction. The European Union, supported by the United Kingdom, Norway, Canada, Japan, South Korea and Australia, has restated its commitment to a 2026 adoption timetable. The Marshall Islands, Vanuatu, Tuvalu and Solomon Islands - the original architects of an ambitious shipping levy - have warned that any further delay would be a betrayal of climate-vulnerable states. China has adopted a more nuanced stance, supporting the principle of an economic measure but pressing for common but differentiated responsibilities, with concessional treatment for developing-country shipping. India and Brazil, both significant BRICS voices, have echoed that line. The result is a fluid bloc that broadly favours the levy but is divided on its design.

The UK angle

The UK has unusual standing in this dispute. The IMO is headquartered on the Albert Embankment in London, and the UK delegation has historically played a brokering role between developed and developing-country positions. The current government has aligned closely with EU climate ambitions on shipping, supporting both the levy and the Global Fuel Standard. London-based maritime services - shipbroking at firms such as Clarksons and Braemar, Lloyd's marine insurance underwriters, and the English commercial bar - would all be touched by the regulatory shift, in many cases beneficially as compliance complexity rises.

Market and economic impact

A new layer of trade friction

If the US-EU split hardens, the practical consequence will be a patchwork of overlapping carbon regimes. The EU ETS already prices shipping emissions on voyages to and from European ports, with full coverage from 2026. The UK is consulting on extending its own ETS to domestic and possibly international shipping. The IMO levy, if eventually adopted without US support, would sit on top of these regional schemes for non-US trades but might be subject to retaliatory measures on US routes. The cost of compliance, hedging and legal advice for shipping companies and their charterers would rise materially.

Inflation pass-through

Shipping carbon costs ultimately feed into the price of imported goods. UK consumer price Inflation is already exposed to freight Volatility following Houthi-related disruption to Red Sea routes, which has lengthened voyages and raised container rates. The Bank of England has flagged shipping costs as a contributor to goods-price persistence. A levy at the upper end of the 150 to 300 dollar range, fully passed through, could add several hundred dollars to the cost of a 40-foot container moved on long-haul routes. The macro impact would be modest but measurable, equivalent to perhaps 10 to 20 basis points on UK headline CPI in a full pass-through scenario, concentrated in goods categories such as electronics, apparel and household equipment.

Capital-expenditure/">Capital Expenditure signal

The deeper economic effect runs through Capital allocation. A credible global carbon price would accelerate orders for dual-fuel vessels capable of running on methanol, ammonia or LNG, and would underwrite Investment in green fuel production, port bunkering infrastructure and onshore power Supply. A protracted dispute, by contrast, encourages a wait-and-see posture. The order book for alternative-fuel newbuilds, which had been growing, may plateau if owners conclude that the regulatory path is unclear. That has implications for shipyards, classification societies and the engine makers - Wartsila, MAN Energy Solutions, Hyundai Heavy - that Supply the sector.

Investor implications

Sectors and stocks in the line of sight

UK investors with exposure to global trade themes should view the IMO dispute as a long-running rather than a binary event. Several listed pockets are sensitive to the outcome:

  • Container lines: Maersk, Hapag-Lloyd, ZIM and Mediterranean Shipping Company (privately held but a major customer of listed suppliers) face direct compliance costs but have proven able to Surcharge customers when fuel and regulatory costs rise.
  • Tanker operators: Frontline, DHT Holdings and International Seaways carry crude and product cargoes on long voyages where levy exposure would be highest.
  • Dry bulk: Star Bulk Carriers and Golden Ocean would see costs rise on iron ore, coal and grain trades.
  • LNG carriers: Flex LNG and Cool Co already operate relatively low-carbon fleets and could benefit on a relative basis.
  • Alternative fuels Supply chain: Methanex in methanol, fertiliser-linked ammonia producers, biofuel refiners and LNG bunkering specialists would see Demand profiles shift with the regulatory path.

The London market itself offers indirect exposure through Clarksons, Braemar, the Lloyd's insurance ecosystem accessed via names such as Beazley, Hiscox and Lancashire, and energy majors with bunker fuel businesses including Shell and BP.

Carbon and Commodity markets

Carbon price benchmarks would also feel the dispute. The EU Allowance market has already absorbed shipping Demand, and a credible IMO levy would create a parallel price signal that could tighten correlations between regional carbon markets over time. Conversely, a stalled IMO process could weigh on sentiment in voluntary carbon and shipping-linked offset markets. Investors in carbon ETFs and Commodity index products with energy weightings should monitor the read-across.

Currency and rates

A persistent US-EU regulatory split is mildly negative for the dollar against the euro and sterling at the Margin, as it reinforces a narrative of US institutional Withdrawal. The effect is unlikely to dominate macro drivers but adds to the basket of factors that gilts and bund traders are weighing as they assess the relative credibility of the two policy regimes.

Risks

Risk of fragmentation

The clearest risk is regulatory fragmentation. If the IMO fails to deliver a global instrument, the EU ETS, UK ETS, a possible Chinese national scheme and various unilateral port-state measures will Fill the vacuum. Compliance complexity rises, arbitrage opportunities open and the risk of trade disputes escalates. For investors, the implication is a wider dispersion of outcomes for shipping equities and a higher cost of Capital for the sector as a whole.

Risk of dilution

Even if a deal is reached, the levy could be diluted. A figure at the lower end of the 150 dollar range, with broad exemptions for developing-country tonnage and a long phase-in, would deliver weaker emissions reductions and a less powerful Investment signal. Pacific island states have warned they would not support a watered-down package and could veto adoption, potentially collapsing the negotiation entirely.

Geopolitical spillover

The dispute does not exist in isolation. It interacts with the EU CBAM, with trade tensions over electric vehicles and steel, and with the broader US-China strategic competition. A breakdown at the IMO would weaken the multilateral system at a moment when COP31, the next round of CORSIA aviation negotiations and the global plastics treaty all need functional UN diplomacy. Investors should be alert to second-round effects on related regulatory files.

Litigation and stranded Assets

For shipowners, regulatory uncertainty translates into asset-life risk. Vessels ordered today will trade for 25 years. If carbon costs rise sharply mid-life, fuel-inefficient ships face accelerated obsolescence. Conversely, premature Investment in alternative-fuel tonnage that lacks bunkering infrastructure can also strand Capital. Litigation risk is rising, particularly for vessels caught between conflicting regional regimes.

Outlook

Three plausible scenarios

The base case for many observers is a delayed but ultimately approved IMO measure, with adoption slipping from 2026 to 2027 and entry into force around 2028. The levy in this scenario lands in the middle of the proposed range, with Revenue recycling skewed to developing-country support. The US declines to ratify but does not actively block enforcement on non-US flagged vessels, mirroring its position on the Law of the Sea Convention.

A more bearish scenario sees the negotiation stall indefinitely, with the EU and a coalition of like-minded states proceeding via regional and unilateral measures. Shipping decarbonisation continues but at a slower pace, and the sector becomes a cautionary tale about the limits of multilateralism under great-power contestation.

A more constructive scenario, less likely on current evidence, would see Washington return to the table after domestic political shifts, perhaps tying engagement to concessions on EU CBAM treatment of US exports. A grand bargain linking shipping, aviation and trade-carbon policy is conceivable but would require political Capital that is in short Supply.

Watch points for the next twelve months

UK investors should track several near-term markers. The MEPC 84 session in spring 2026 is the principal event. The position of China heading into that meeting will be decisive, as will any shift in the Indian and Brazilian stance. EU ETS Revenue flows from shipping in the first full compliance year will provide a natural experiment in pass-through Economics. UK Treasury and Department for Transport consultations on UK ETS extension are due to report. And the trajectory of US-EU trade relations more broadly will set the mood music for the IMO file.

Conclusion

The American delay at the IMO is not simply a procedural skirmish. It is a stress test for the proposition that the world can still negotiate binding, sector-wide climate rules under a UN umbrella in an era of fractured great-power politics. For UK investors, the immediate financial implications are manageable but the second-order effects on global carbon pricing architecture, on UK-listed shipping and maritime services, and on the credibility of the multilateral system are substantial. The story will play out over years, not weeks, and patience will be required. The outcome at MEPC 84 will tell investors a great deal about whether the next phase of decarbonisation is to be global, regional or simply contested.